A hard disk drive typically contains one or more disks clamped to a rotating spindle, at least one head for reading data from and/or writing data to the surfaces of each disk, and an actuator utilizing linear or rotary motion for positioning the head(s) over selected data tracks on the disk(s). A rotary actuator is a complex assembly that couples slider(s) on which head(s) are attached to a pivot point that allows each head to sweep across a surface of a rotating disk.
A disk and a slider can each be extremely smooth, and strong adhesive forces can prevent the disk from rotating during a “power-on” cycle if the slider is landed on the disk surface. To prevent this phenomenon, modern hard disk drives typically use one of two solutions: (1) a narrow area close to the disk center is textured using a laser to create a special landing zone on the disk, or (2) a load-unload ramp is positioned either adjacent to the disk or just over the disk surface. Where a load-unload ramp is used, the head is “parked” by moving the suspension beyond the disk area and sliding the suspension onto a ramp. Parking the head on the ramp can increase the drive's non-operational shock resistance and prevent accidental damage during transportation. To prevent damage to the head during unexpected power loss, the ramp must be sufficiently shallow such that the hard disk drive has enough remaining power to drive the head up the ramp. A shallow ramp extends over more tracks at the outer diameter of the disk than a steep ramp and can cost valuable disk space; however, where a steep ramp is used a hard disk drive may not have sufficient power to properly position the head.